Size and weight limits not to be exceeded; powers of local authorities

(A) It is unlawful for a person to drive or move or for the owner to cause or knowingly to permit to be driven or moved on a highway a vehicle of a size or weight exceeding the limitations stated in this article or otherwise in violation of this article. The maximum size and weight of vehicles herein specified is lawful throughout the State, and local authorities shall have no power or authority to alter these limitations except as express authority may be granted in this article. Provided, that municipalities and their franchisees may operate combinations of vehicles of not more than four units and not more than sixty-five feet in length on city streets within their corporate limits and the operation of these combinations of units is limited to speeds not in excess of twenty miles an hour, and these combination units must be equipped with brakes meeting braking requirements of Section 56-5-4860 and the rear vehicle must be equipped with at least one stoplight. (B) The Transport Police Division of the Department of Public Safety has exclusive authority in this State for enforcement of the commercial motor vehicle carrier laws, which include Federal Motor Carrier Safety Regulations, Hazardous Material Regulations, and size and weight laws and regulations.